The surface of the substrate such as plastic, metal, ceramics, fiber, woods, concrete, paint or the like have been treated for improved use in a variety of fields. For example, a method for treating a surface containing macromolecules includes; coating with a fluorosilane coupling agent to provide water and oil repellancy; coating with a wax to provide lubrication; coating with a polyvinyl alcohol to provide hydrophilicity; and coating with a suspension of a fluorocarbon-based polymer in order not to catch dirt on the surface of a substrate. The above-mentioned methods are recognized in the field.
However, coating films of the prior art have a relatively weak binding strength to the substrates containing macromolecules. Consequently, if the substrates are wiped by a cloth or washed repeatedly, coating films are peeled off from the substrate and lose the finishing effect. Moreover, coating films of the prior art have a large number of pin-holes on their surfaces because molecules arrange in various directions therein, thus deteriorating the property. Moreover, fluorocarbon-based polymer coating films are deficient in transparency so that they cannot be used for the treatment of optical materials that require transparency.
Methods for manufacturing chemically adsorbed monomolecular films are suggested by the inventor of this invention. See, for example, Japanese Laid-Open Patent No. (Tokkai-Hei) 4-132637, Japanese Laid-Open Patent No. (Tokkai-Hei) 4-221630, Japanese Laid-Open Patent No. (Tokkai-Hei) 4-367721 which are incorporated by reference. Such films are free from peeling off from the substrates, being pin-hole free, having thickness on the order of nanometers, and having a high transparency, in other words, transparency and lustering properties.
However, according to the conventional method for manufacturing chemically adsorbed films, the films were formed by a dehydrochloric reaction between a chlorosilane-based surface active agent and the surface of a substrate. Consequently, harmful hydrochloric acid gas can generate during the formation of such films. Also certain methods have attempted to form films by a dealcohol reaction by way of an alkoxysilane surface active agents. However, since this reaction proceeds slowly, films are not easily formed. The method of using a dealcohol catalyst is also possible, but the surface active agent cross-links with the moisture content inthe air and loses the activity if only the dealcohol catalyst is added. In other words, if the finishing agent includes moisture, the surface active agent cross-links before reacting to the surface of the substrate so that the reaction at the interface of solid and liquid is prevented, thus making chemically adsorption difficult.